Many cities and municipalities face increasing problems of obtaining potable water adequate for their needs. In the arid southwest portions of the United States, land is often not used because of a lack of water. Disputes can arise when a limited amount of water is shared by cities and agricultural areas. Some cities often limit their watering of lawns, golf courses, etc. A contributing factor to the worsening water shortage is that cities do little or nothing to improve the way their waste water is processed after use by the consumer.
Typically, this waste water is sent to a sewage processing facility where it is treated and discharged into a river or the like where it flows downstream for other users.